Low impedance oxide resistant grounded capacitor for an AIMD

• US 9,427,596 B2
• Filed: 08/14/2015
• Issued: 08/30/2016
• Est. Priority Date: 01/16/2013
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Woods, Jason, Brendel, Richard L., Stevenson, Robert A., Williams, Christopher Michael, Naugler, Robert, Frysz, Christine A.
• Primary Examiner(s): GETZOW, SCOTT M
• Application Number:
  US14/826,229
• Publication Number:
  US 20150343224A1
• Time in Patent Office: 382 Days
• US Class Current: 1/1
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01G 2/02 Mountings
• CPC Class Codes: H01G 4/228 Terminals
• CPC Class Codes: H01G 4/35 Feed-through capacitors or anti-noise capacitors
• CPC Class Codes: H01G 4/40 Structural combinations of fixed capacitors with other electric elements, the structure mainly consisting of a capacitor, e.g. RC combinations
• CPC Class Codes: H01R 13/7195 with planar filters with openings for contacts
• CPC Class Codes: H02G 15/013 Sealing means for cable inlets inlets for cables filled with, or surrounded by, gas or oil H02G15/32
• CPC Class Codes: H03H 1/00 Constructional details of impedance networks whose electrical mode of operation is not specified or applicable to more than one type of network constructional details of electromechanical transducers H03H9/00
• CPC Class Codes: H03H 2001/0042 Wound, ring or feed-through type capacitor
• CPC Class Codes: H03H 2001/0085 Multilayer, e.g. LTCC, HTCC, green sheets

Abstract

A hermetically sealed filtered feedthrough assembly for an AIMD includes an electrically conductive ferrule with an electrically conductive extension at least partially extending into the ferrule opening. An electrically non-conductive insulator hermetically seals the ferrule opening. An electrically conductive pathway is hermetically sealed and disposed through the insulator between a body fluid and device side. A filter capacitor is located on the device side. A first low impedance electrical coupling is between a first metallization of the filter capacitor and the pathway. A ground conductor is disposed through the filter capacitor in non-conductive relation with the at least one active and ground electrode plates, where the ground conductor is electrically coupled to the extension of the ferrule. An oxide-resistant metal addition is disposed on the device side and electrically couples the ground conductor to the second metallization of the filter capacitor.

Claims

1. A hermetically sealed filtered feedthrough assembly for an implantable medical device, the filtered feedthrough assembly comprising:

a) a ferrule of an electrically conductive material, the ferrule comprising a ferrule sidewall defining a ferrule opening, wherein the ferrule comprises a ferrule extension partially extending into the ferrule opening;

b) an insulator of electrically non-conductive material, the insulator comprising an outer insulator surface extending longitudinally from a first insulator end to a second insulator end, wherein the insulator is hermetically sealed to the conductive ferrule sidewall in the ferrule opening, and wherein the insulator has at least a first insulator bore extending there through to the first and second insulator ends;

c) a filter capacitor, comprising;

i) a dielectric comprising an outer dielectric surface extending longitudinally from a first dielectric end to a second dielectric end, wherein the second dielectric end is longitudinally disposed adjacent to the first insulator end;

ii) at least one active electrode plate supported by the dielectric in an interleaved, partially overlapping relationship with at least one ground electrode plate; and

iii) at least a first and a second dielectric bores extending through the dielectric to the first and second dielectric ends;

d) a first metallization electrically contacted to the at least one active electrode plate in the first dielectric bore;

e) a conductor comprising an electrically conductive material hermetically sealed and disposed through the first insulator bore, wherein the conductor is in a non-conductive relation with the conductive ferrule and extends through the dielectric bore so that a first conductor end is adjacent to the first dielectric end and a second conductor end is adjacent to the second insulator end;

f) a first electrically conductive material coupling the conductor in the dielectric bore to the first metallization coupled to the active electrode plate;

g) a second metallization electrically contacted to the ground electrode plate at at least a portion of the outer dielectric surface; and

h) a ground conductor extending through the dielectric in a non-conductive relation with the active and ground electrode plates, wherein the ground conductor has a first ground conductor end spaced from a second ground conductor end, and wherein the second ground conductor end is electrically and physically coupled to the ferrule extension; and

i) an oxide-resistant metal addition electrically and physically coupling from the second metallization contacted to the ground electrode plate at the outer dielectric surface to a location on the ground conductor spaced from the second ground conductor end coupled to the ferrule extension.

2. The assembly of claim 1, wherein the dielectric is disposed between where the oxide-resistant metal addition is coupled to the ground conductor and the second ground conductor end coupled to the ferrule extension.

3. The assembly of claim 2, including an insulative sheet partially disposed between the first dielectric end and the oxide-resistant metal addition.

4. The assembly of claim 1, wherein the oxide-resistant metal addition is coupled to the ground conductor intermediate the second insulator end and the second ground conductor end coupled to the ferrule extension.

5. The assembly of claim 4, including an insulative sheet disposed between the second dielectric end and the insulator.

6. The assembly of claim 1, wherein the oxide-resistant metal addition is coupled to the second metallization contacted to the ground electrode plate by a second electrically conductive material.

7. The assembly of claim 6, wherein the second electrically conductive material comprises a plurality of connections electrically coupling the oxide-resistant metal addition to the second metallization.

8. The assembly of claim 1, wherein the oxide-resistant metal addition is coupled to the ground conductor by a third electrically conductive material.

9. The assembly of claim 1, wherein the oxide-resistant metal addition comprises a different material as compared to the ferrule.

10. The assembly of claim 1, wherein the oxide-resistant metal addition comprises a noble metal.

11. The assembly of claim 1, wherein the oxide-resistant metal addition is selected from the group consisting of gold, platinum, palladium, silver, and combinations thereof.

12. The assembly of claim 1, wherein a grounding pathway is defined from the second metallization, through the oxide-resistant metal addition and to the ferrule extension.

13. The assembly of claim 12, wherein a total resistance of the grounding pathway is less than 5 milliohm.

14. The assembly of claim 12, wherein a total resistance of the grounding pathway is less than 1 milliohm.

15. The assembly of claim 12, wherein a total inductance of the grounding pathway is less than 10 nanohenries.

16. The assembly of claim 12, wherein a total inductance of the grounding pathway is less than 1 nanohenrie.

17. The assembly of claim 1, wherein first conductor end is spaced from the first dielectric end and a second conductor end is spaced from the second insulator end.

18. The assembly of claim 1, wherein the oxide-resistant metal addition is selected from the group consisting of an L-shaped pad and an L-shaped pad with cutouts.

19. The assembly of claim 1, wherein the filter capacitor is a feedthrough capacitor.

20. The assembly of claim 1, wherein the conductor comprises a leadwire selected from the group consisting of platinum, palladium, silver, and gold.

21. The assembly of claim 1, wherein the first insulator end is flush with the ferrule adjacent to the second dielectric end.

22. The assembly of claim 1, wherein the insulator and the filter capacitor are either circular or rectangular in cross-section perpendicular to their longitudinal extent.

23. A hermetically sealed filtered feedthrough assembly for an implantable medical device, the filtered feedthrough assembly comprising:

a) a ferrule of an electrically conductive material, the ferrule comprising a ferrule sidewall defining a ferrule opening, wherein the ferrule comprises a ferrule extension partially extending into the ferrule opening;

b) an insulator of electrically non-conductive material, the insulator comprising an outer insulator surface extending longitudinally from a first insulator end to a second insulator end, wherein the insulator is hermetically sealed to the conductive ferrule sidewall in the ferrule opening, and wherein the insulator has at least a first insulator bore extending there through to the first and second insulator ends;

c) a filter capacitor, comprising;

i) a dielectric comprising an outer dielectric surface extending longitudinally from a first dielectric end to a second dielectric end, wherein the second dielectric end is longitudinally disposed adjacent to the first insulator end;

ii) at least one active electrode plate supported by the dielectric in an interleaved, partially overlapping relationship with at least one ground electrode plate; and

iii) at least a first and a second dielectric bores extending through the dielectric to the first and second dielectric ends;

d) a first metallization electrically contacted to the at least one active electrode plate in the first dielectric bore;

e) a conductor comprising an electrically conductive material hermetically sealed and disposed through the first insulator bore, wherein the conductor is in a non-conductive relation with the conductive ferrule and extends through the dielectric bore so that a first conductor end is spaced from the first dielectric end and a second conductor end is spaced from the second insulator end;

f) a first electrically conductive material coupling the conductor in the dielectric bore to the first metallization coupled to the active electrode plate;

g) a second metallization electrically contacted to the ground electrode plate at at least a portion of the outer dielectric surface; and

h) a ground conductor extending through the dielectric in a non-conductive relation with the active and ground electrode plates, wherein the ground conductor has a first ground conductor end spaced from a second ground conductor end, and wherein the second ground conductor end is electrically and physically coupled to the ferrule extension; and

i) an oxide-resistant metal addition electrically and physically coupling from the second metallization contacted to the ground electrode plate at the outer dielectric surface to a location on the ground conductor spaced from the second ground conductor end coupled to the ferrule extension,

j) wherein a grounding pathway is defined from the second metallization, through the oxide-resistant metal addition and to the ferrule extension, wherein a total resistance of the grounding pathway is less than 5 milliohm and wherein a total inductance of the grounding pathway is less than 10 nanohenries.

24. The assembly of claim 23, wherein the total resistance of the grounding pathway is less than 1 milliohm and the total inductance of the grounding pathway is less than 1 nanohenrie.

25. The assembly of claim 23, wherein the dielectric is disposed between where the oxide-resistant metal addition is coupled to the ground conductor and the second ground conductor end coupled to the ferrule extension.

26. The assembly of claim 23, wherein the oxide-resistant metal addition is coupled to the ground conductor intermediate the second insulator end and the second ground conductor end coupled to the ferrule extension.

27. A hermetically sealed filtered feedthrough assembly for an implantable medical device, the filtered feedthrough assembly comprising:

a) a ferrule of an electrically conductive material, the ferrule comprising a ferrule side all defining a ferrule opening, wherein the ferrule comprises a ferrule extension partially extending into the ferrule opening;

b) an insulator of electrically non-conductive material, the insulator comprising an outer insulator surface extending longitudinally from a first insulator end to a second insulator end, wherein the insulator is hermetically sealed to the conductive ferrule sidewall in the ferrule opening, and wherein the insulator has at least a first insulator bore extending there through to the first and second insulator ends;

c) a filter capacitor, comprising;

i) a dielectric comprising an outer dielectric surface extending longitudinally from a first dielectric end to a second dielectric end, wherein the second dielectric end is longitudinally disposed adjacent to the first insulator end;

ii) at least one active electrode plate supported by the dielectric in an interleaved, partially overlapping relationship with at least one ground electrode plate; and

iii) at least a first and a second dielectric bores extending through the dielectric to the first and second dielectric ends;

d) a first metallization electrically contacted to the at least one active electrode plate in the first dielectric bore;

e) a conductor comprising an electrically conductive material hermetically sealed and disposed through the first insulator bore, wherein the conductor is in a non-conductive relation with the conductive ferrule and extends through the dielectric bore so that a first conductor end is spaced from the first dielectric end and a second conductor end is spaced from the second insulator end;

f) a first electrically conductive material coupling the conductor in the dielectric bore to the first metallization coupled to the active electrode plate;

g) a second metallization electrically contacted to the ground electrode plate at at least a portion of the outer dielectric surface; and

h) a ground conductor extending through the dielectric in a non-conductive relation with the active and ground electrode plates, wherein the ground conductor has a first ground conductor end spaced from a second ground conductor end, and wherein the second ground conductor end is electrically and physically coupled to the ferrule extension; and

i) an oxide-resistant metal addition electrically and physically coupling from the second metallization contacted to the ground electrode plate at the outer dielectric surface to a location on the ground conductor spaced from the second ground conductor end coupled to the ferrule extension;

j) a second electrically conductive material coupling the oxide-resistant metal addition to the second metallization contacted to the ground electrode plate by; and

k) a third electrically conductive material coupling the oxide-resistant metal addition to the ground conductor,

l) wherein a grounding pathway is defined from the second metallization, the second electrically conductive material, through the oxide-resistant metal addition, to the ferrule extension then the third electrically conductive material and the ground conductor.

28. A hermetically sealed filtered feedthrough assembly for an implantable medical device, the filtered feedthrough assembly comprising:

a) a ferrule of an electrically conductive material, the ferrule comprising a ferrule sidewall defining a ferrule opening, wherein the ferrule comprises a ferrule extension partially extending into the ferrule opening;

b) an insulator of electrically non-conductive material, the insulator comprising an outer insulator surface extending longitudinally from a first insulator end to a second insulator end, wherein the insulator is hermetically sealed to the conductive ferrule sidewall in the ferrule opening, and wherein the insulator has at least a first insulator bore extending there through to the first and second insulator ends;

c) a filter capacitor, comprising;

i) a dielectric comprising an outer dielectric surface extending longitudinally from a first dielectric end to a second dielectric end, wherein the second dielectric end is longitudinally disposed adjacent to the first insulator end;

ii) at least one active electrode plate supported by the dielectric in an interleaved, partially overlapping relationship with at least one ground electrode plate; and

iii) at least a first and a second dielectric bores extending through the dielectric to the first and second dielectric ends;

d) a first metallization electrically contacted to the at least one active electrode plate in the first dielectric bore;

e) a conductor comprising an electrically conductive material hermetically sealed and disposed through the first insulator bore, wherein the conductor is in a non-conductive relation with the conductive ferrule and extends through the dielectric bore so that a first conductor end is adjacent to the first dielectric end and a second conductor end is adjacent to the second insulator end;

f) a first electrically conductive material coupling the conductor in the dielectric bore to the first metallization coupled to the active electrode plate;

g) a second metallization electrically contacted to the ground electrode plate at at least a portion of the outer dielectric surface; and

h) a ground conductor extending through the dielectric in a non-conductive relation with the active and ground electrode plates, wherein the ground conductor has a first ground conductor end spaced from a second ground conductor end, and wherein the second ground conductor end is electrically and physically coupled to the ferrule extension; and

i) an oxide-resistant metal addition electrically and physically coupling from the second metallization contacted to the ground electrode plate at the outer dielectric surface to the ferrule electrically connected to the ground conductor.